What is POSIX TZ and what is Olson? How can I tell?
• There are two types of TZ variable setting supported in Solaris. One is so called POSIX timezone, and the other is called Olson. • POSIX TZ has a form of “std offset dst offset” (eg PST8PDT) which TZ string itself represents timezone abbreviation and offset from UTC. It “dst offset” was given, US DST rules are used. The default US rules are hardcoded in libc. Therefore, it you are using this form, they need libc patches. • The other form of TZ variable (Olson) is of the form “US/Pacific”, which points to the file under /usr/share/lib/zoneinfo and each file contains timezone definitions. There are a lot of files under the directory for many regions. If you are using this form, you need zoneinfo patches. • See man page of environ(5).
